I just recently upgraded from my home built 10" sub to the X-12. I plugged it in, turned it on and my son couldn't wipe this silly grin off his face. I have a rather small room so I have it in max extension and it definitely plays lower than its predecessor-no surprise.
This is actually the second X-12 I have owned. Unfortunately the first one was damaged. On of the port broke of the flange and was rattling inside the housing. But, of course, that why I deal with Outlaw. On phone call and the old one is on it's way back and the new one is on it's was over.
On the minus side, I had built the 10" sub into my entertainment unit and thus it was totally hidden. There's no hiding the X-12. You can disguise it as an end table. It's pretty enough to serve that function.
I would definitely recommend it, though I have no direct comparison to other 12" subs.
Aperion Verus Grand Towers & Bookshelves, Verus Forte Center, Infinity Surrounds, Ultra-X12
Oppo BDP-103, XBOX360, Xbox One
Samsung 51" Plasma
RR2150 w/Klipsch SCR-2